MRI-based cell tracking of OATP-expressing cell transplants by pre-labeling with Gd-EOB-DTPA

Purpose To detect cell transplants labeled with a clinical gadolinium-based contrast agent as hyperintense signals using a clinically familiar T1-weighted MRI protocol. Methods HEK293 cells were stably transduced to express human OATP1B3, a hepatic transporter that transport Gd-EOB-DTPA into cells that express the transporters, the intracellular accumulation of which cells causes signal enhancement on T1-weighted MRI. Cells were labeled in media containing Gd-EOB-DTPA for MRI evaluation and indocyanine green for cryofluorescence tomography validation. Labeled cells were injected into chicken hearts, in vitro, after which MRI and cryofluorescence tomography were performed in tandem. Results OATP1B3-expressing cells had substantially reduced T1 following labeling with Gd-EOB-DTPA in culture. Following their implantation into chicken heart, these cells were easily identified in T1-weighted MRI. Cryofluorescence tomography validated that the areas of signal enhancement in MRI overlapped with areas of indocyanine green signal, indicating that signal enhancement was due to the transplanted cells. Conclusion OATP1B3-expressing cells can be pre-labeled with Gd-EOB-DTPA prior to injection into tissue, affording the use of clinically familiar T1-weighted MRI to robustly detect cell transplants.